Field of the Invention
The present invention relates to a container cover. In particular, it relates to a device used for covering the open top of vehicular containers that are carried by or on trucks, trailers, roll-on/roll-off hoists, and similar vehicles.
It is well known to provide a cover for the material carrying container of a truck. Such covers are particularly useful when transporting loose materials such as garbage, sand, or gravel, to prevent the load from being blown out of the container by the wind. Additionally, the cover protects the load from contamination. Many examples of container covers are known in the prior art. A popular arrangement for covering a truck container is to use a tarpaulin (or xe2x80x98tarpxe2x80x99) or other flexible cover, mounted upon a roller assembly adjacent one end of the truck container. The tarp is pulled from one end of the truck to the other by means of a front-to-rear pivot arm assembly.
There are many variations of pivot arm style covering assemblies that pull a flexible cover over the top of an open top container mounted to or carried on a truck chassis. Typically the pivot arms are powered between a first and second position on the truck by a spring force or hydraulic cylinder that is coupled to the pivot arms in the vicinity of the pivot point. The pivot arms may be fixed in length or variable in lengths by way of a telescoping feature. Whether the arms are fixed or variable in length, the cross-member or cover support element and pivot arms are rigidly connected, thereby tying the two pivot arms together as described for example in U.S. Pat. No. 5,829,818. The tying of the two pivot arms together through a rigid connection with the cross-member, helps the arms to work in unison with each other as they pivot together between the first and second positions on the truck, and to keep the arms at a fixed width between each other as they pivot about their pivot point.
The problems with this type of rigid connection between pivot arms and cross-member are several. First, if the arms come into contact with the container, or any objects protruding from the container, both arms are likely to be affected and possibly be damaged together along with the cross-member tying the arms together. Excessive external force experienced by one arm, can be transmitted through the rigid cross-member to the other arm, causing damage to both arms and cross-member. Also, with a rigid cross member, telescopic arms must be synchronized very closely in order to prevent the arms from binding as they telescope.
The present invention has been devised in order to address the deficiencies in the prior art.
According to the present invention there is provided a cover assembly for the container of the vehicle having a container having first and second ends; wherein the cover assembly comprises a retractable cover having a first end attached to a roller assembly and a second end attached to a cover support element. The cover support element has first and second ends, each of which is joined by means of a union at the upper end of a pair of pivot arms, each of said pivot arms being pivotable about a lower end thereof at a point intermediate the first and second ends of the container and adjacent the bottom of the container, between a first position in which the cover support element is adjacent the first end of the container and a second position in which the cover support element is adjacent the second end of the container. The union between the pivot arms and cover support element is a flexible joint.
Preferably, the flexible joint incorporates a pivoting element between the cover support element and the pivot arms, throughout a vertical plane parallel with the pivot arms.
Preferably, the flexible joint incorporates a sliding element between the cover support element and the pivot arms, through the longitudinal axis of the cover support element.
Preferably, the flexible joint incorporates an axial rotation element between the cover support element and the pivot arms, around the longitudinal axis of the cover support element.
Suitably, the flexible joint is a ball joint assembly. Alternatively the flexible joint may be an assembly of flexible rubber, spring material, or other suitable material.